Belt conveyer.



PATENTBD JUNE 25,- 1907.

E. e. THOMAS. BELT GONVEYER.

I APPLICATION FILED 0(JT.19\.1906.

an-i.

EDWARD G. THOMAS, OF BROOKLINE, MASSACHUSETTS.

, BELT CONVEYER.

Specification of Letters Patent.

Patented June 25, 1907.

Application filed October 19,1906. Serial No- 339,629-

To whom it may concern:

Be it known that I, EDWARD G. TnoMAs, of Brookline, county of Norfolk, State of Massachusetts, have invented and produced certain new and useful Improvements in Belt Conveyors, of which the following is a specification.

The transportation of material of all kinds by means of moving belts supported by rotatable rollers, is an extensive practice in all branches of the arts. When this device is applied to the carrying of granulated material, the amount which can be transported is limited, by the tendency of the material to spread to the edge of the belt and fall from it. No greater amount can be carried than that which will form a pile, highest in the center of the belt and having an angle of repose, under the operating conditions of the-belt, insufficient to cause the edge of the pile to extend to the edge of the belt. In order to increase the capacity of a given width of belt, it is common practice to raise the edges of the belt above the center by means of inclined rollers, usually termed troughing idlers. Then this is done, it is obvious that a greater amount of material can be placed 011 belt before the edges of the pile will extend to the edges of the belt. When troughing idlers, consisting of two or more pulleys, turning on axes inclined to one another, are used, the belt is forced by its weight and that of its load to make a bend at the point where the surfaces of the pulleys meet, as each portion of the belt passes over the idlers, while between them the belt will take a flatter and more evenly distributed curve. A bending strain, due to a forward and back motion, is therefore put on that portion of the belt which registers with the meeting angle of the pulleys, as many times per minute as the distance between idlers is contained in the speed of the belt per minute. The result of this repeated strain concentrated along a line of the belt, is the rapid destruction of the belt on this line long before other portions of the belt are worn out. A variety of devices for adding to the strength, or increasing the pliability of the belt atthese points of greatest wear, have been tried with varying degrees of success.

My invention consists in substituting for the pulleys, set at an angle, ordinarily used, under the side of the belt on which the load is placed (usually called the working side in contradistinction to the lower part or return side), a flexible troughing roller supported at the ends in bearings, in combination with a supporting roller, mounted in bearings placed below and to one side of the bearings for the troughing roller; The relative diameters of the flexible troughing roller and the supporting roller are such that the flexible roller must sag in the center, be fore a belt placed upon the idler can come in contact with both rollers. A preferable construction will be such that the weight of the belt and load will be suflicient to cause a sufficient sagging of the flexible troughing roller to permit the belt to come in contact with, and be supported for a part of its width by the lower roller. Inasmuch as this contact will occur at the center of the belt, it is obvious that the greater part of the weight of the belt and its load will be supported by this lower roller, while the flexible troughing roller will serve to bend upward the edges of the belt into the troughed form desired.

My invention is illustrated by the drawings which accompany and form a part of these specifications.

In these drawings Figure 1 is a side elevation of the idler, showing the belt in cross section, illustrating the position occu ied by its parts, when the belt is loaded wit material. Fig. 2 is an end elevation of this idler, showing a portion of side View of belt.

In these drawings 1 is a flexible roller, formed preferably by a steel spring. Each end of this roller 1 is secured to a rotatable flange 2, in which the axially projecting ends of the spring can be securely fastened. Said flange 2 is supported by box 3, which is pivotally mounted in a supporting bracket 4, secured to the frame-work 7 of the conveyer. A roller or pulley 5 is rotatably mounted in bearings 6, below and to one side of the bearings for the flexible roller. The bearings 6 are secured to the frame-work 7 of the conveyor. The conveyor belt is marked 8.

I prefer in the construction of this device to put the spring roller in' place with a slight initial tension, so that the bearings 3 will be thrust bearings at all times. These bearings are pivoted in order that the ends of the spring roller may occupy positions varying according to the deflection of the roller. Inasmuch as the length of the spring will be increased as it is deflected by the weight of the belt and load, the tension of the spring and its supporting force will increase with an increase of load upon the belt, but it is presumed that the greater part of the Weight of the belt and load will be supported upon the lower roller 5.

There will obviously be no point along the spring roller at which a sharp bend will occur, so that the belt will be bent at an easy curve, and no point will be strained beyond the ability of the belt to stand the work.

The roller 5 may consist of a flexible roller similar to the trougliing roller, in which case it will be of greater strength than the trough: ing roller, so as to have less deflection under load. A preferred construction is, however, to make the roller 5, from one or more inflexible rollers or pulleys, rotatable on a stationary shaft, or from one or more pulleys secured to a rotatable shalt. Under a reasonable constant load the pivots for boxes 3 may be omitted and the boxes secured in a fixed inclined position, but for variable loads it Will be desirable to follow the construction shown in the drawing.

Having thus fully described my invention, I desire to claim and secure by Letters Patent of the United States the following:,

1. In a belt conveyer the combination of a belt, belt-supporting rollers and flexible belttroughing rollers, in adjacent contact with the load-carrying side of said belt, substantially as described.

2. In a belt conveyer the combination of a belt, a belt-supporting roller, and a flexible belt-troughing roller, said supporting roller being pivoted below and to one side of the bearing for said troughing roller, substantially as described.

3. In a supporting device for the load-carrying side only of belt conveyers the combination of a belt-supporting roller and a flexible belt-troughing roller, substantially as described.

4. In a supporting device for the load-carrying side of belt conveyers the combination of a belt-supporting roller and a flexible belttroughing roller, said supporting roller being pivoted below and to one side of said troughing roller, substantially as described.

5. In a supporting device for the load-carrying side of belt conveyers the combination of a belt-supporting roller, bearings for said roller, a flexible belt-troughing roller, bearings for said troughing roller and supporting means for all said bearings, substantially as described.

6. In a supporting device for the load-carrying side of belt conveyers the combination of a belt-supporting roller, bearings for said roller, a flexible belt-troughing roller, pivoted bearings for said troughing roller and sup porting means for all said bearings, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of the two subscribing Witnesses.

EDIVARD G. THOMAS.

Witnesses:

M. P. JoHNsoN, HENRY DECKER JACKSON. 

